This disclosure relates to a gas turbine engine mid-turbine frame tie rod arrangement.
A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustor section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.
A mid-turbine frame (MTF) is arranged axially between the high and low pressure turbines. One example MTF includes inner and outer cases secured to one another with tie rods extending radially between the cases. Airfoils are provided between the inner and outer cases, and the tie rods extend through some of the airfoils.
In one arrangement, opposing ends of the tie rod are threaded. Fasteners are secured to the threaded end to clamp the MTF assembly together. An anti-rotation feature may be provided at an inner end of the tie rod and the inner case. The feature prevents the rotation of the tie rod about its longitudinal axis thereby precluding interference with the airfoils, and loosening of a nut securing the rod to the inner case, during assembly of the MTF.